You Were Injured in a Motorcycle Accident in California. Lane Splitting Is Legal, Helmets Are Required for All Riders, and Pure Comparative Fault Applies.

Motorcycle Accidents Under California Law

California is the only U.S. state that expressly legalizes lane splitting for motorcycles under Vehicle Code § 21658.1. This creates a distinctive liability framework: the 2023 OmniBike Bill (AB 1909) requires drivers to change lanes entirely when safely passing a motorcyclist, and a driver who struck a lane-splitting rider without complying with this rule is negligent per se.

California Vehicle Code § 27803 requires all motorcycle riders and passengers to wear a U.S. DOT-compliant protective helmet, regardless of age. This applies to all riders — unlike California’s bicycle helmet law (CVC § 21212), which applies only to riders under 18. Riding without a helmet does not bar recovery but may support a comparative fault argument limited to head injuries: a defendant can argue that head injuries would have been less severe with a compliant helmet, but only as to head injury claims and only with medical expert testimony establishing the specific causal connection.

Left-turn failures to yield are the most common cause of fatal motorcycle accidents. California Vehicle Code § 21801 requires drivers turning left to yield to all oncoming traffic — including motorcycles — that is close enough to constitute an immediate hazard. The "I didn’t see the motorcycle" defense does not excuse the failure to yield; every driver has a duty to look for all road users before initiating a turn, and failure to perceive an approaching motorcycle through negligent observation constitutes a breach of that duty.

The two-year statute of limitations under Code of Civil Procedure § 335.1 applies from the date of the accident. Freeway motorcycle accidents are investigated by CHP; city surface street accidents by the local police department. Traffic Collision Reports from freeway accidents are obtainable from the local CHP area office; city street reports from the relevant police department’s records division.

What to Do After a Motorcycle Accident in California

Motorcycle accident evidence is especially time-sensitive. These steps protect both the legal claim and the physical evidence.

1. Call 911. CHP responds to freeway accidents; local police to city streets. The Traffic Collision Report documents Vehicle Code violations, road conditions, and witnesses. Obtain the report number at the scene.
2. Preserve your helmet as physical evidence. Your helmet’s damage pattern documents impact location and force. Do not repair or discard it — in TBI cases, helmet experts analyze the impact zone to correlate with documented brain injuries.
3. Photograph all vehicle positions, lane markings, and contact points before anything moves. In lane-splitting fault disputes, the physical geometry of vehicle positions relative to lane markings is critical evidence.
4. Collect the other driver’s complete information. License, plate, insurance carrier and policy number. If the driver is uninsured, UM/UIM coverage under Insurance Code § 11580.2 is the primary recovery path — notify your insurer immediately.
5. Do not repair or modify the motorcycle before it is documented. Component failures — tire blowouts, brake failures — that contributed to the accident make the motorcycle a product liability evidence item.
6. Seek emergency neurological evaluation. Motorcycle accidents produce high rates of TBI and spinal cord injury. Standard imaging may appear normal despite significant cognitive injury — follow all neurological referrals.
7. File the DMV SR-1 within 10 days. Required when injury, death, or damage exceeding $1,000 occurred under Vehicle Code § 16000.

Your Rights After a Motorcycle Accident in California

The right to lane split legally and recover when other drivers fail to yield

California Vehicle Code § 21658.1 legalizes lane splitting, and the 2023 OmniBike Bill (AB 1909) requires drivers to change lanes entirely when safely passing a two-wheeled vehicle. A driver who made a lane change without fully clearing the adjacent lane and struck a lane-splitting motorcyclist has violated § 22107 (unsafe lane change) and the OmniBike Bill requirement — establishing negligence per se. The motorcyclist’s use of lane splitting, when done within the CHP guidelines, does not constitute contributory fault unless the rider was traveling at a speed substantially faster than surrounding traffic.

The right to recover even without a helmet, subject to comparative fault reduction

California Vehicle Code § 27803 requires all motorcycle riders and passengers to wear DOT-compliant helmets regardless of age. Riding without a helmet does not bar civil recovery — California’s pure comparative fault system prevents any single factor from eliminating recovery entirely. However, a defendant may introduce expert testimony that the plaintiff’s head injuries would have been less severe with a compliant helmet, potentially reducing the non-economic damages assigned to head injury claims. This argument is limited to head injury claims only and requires medical causation testimony.

The right to full damages for catastrophic injuries

Motorcycle accident injuries frequently include traumatic brain injury, spinal cord injury, and multiple orthopedic fractures. California does not cap damages in motorcycle accident cases (MICRA caps apply only to medical malpractice). Life care planning expert testimony is admissible and often required in catastrophic injury cases to establish the present value of future medical expenses and supportive care needs.

How Fault Is Determined in California Motorcycle Accident Cases

Motorcycle accident fault analysis in California applies pure comparative fault to all contributing conduct. Common fault disputes: lane-splitting speed (was the rider traveling at a materially higher speed than surrounding traffic?); lane change compliance (did the driver fully yield or simply maintain distance?); left-turn timing (was the motorcycle close enough to constitute an immediate hazard when the turn began?); and helmet use (does the absence of a helmet support a damages reduction argument on head injury claims?).

The OmniBike Bill (AB 1909, 2023) added a statutory duty for drivers to change lanes when safely passing a motorcyclist — not merely to maintain three feet of distance. A driver who failed to change lanes when a safe gap was available and then made contact with a lane-splitting motorcyclist has violated this statutory duty, establishing negligence per se under Evidence Code § 669.

Multi-defendant scenarios are common in motorcycle accident cases. When a defective road condition — a pothole, missing guardrail, absent warning signs — contributed to the accident, a government entity may face a Government Code § 835 dangerous condition claim alongside the driver negligence claim. Each defendant’s fault is allocated separately under Proposition 51 for non-economic damages.

Insurance Considerations in California Motorcycle Accident Cases

Motorcycle accident cases frequently exceed the at-fault driver’s minimum policy limits given the severity of typical motorcycle injuries. Updated minimums of $30,000/$60,000/$15,000 (January 2025) are particularly inadequate for TBI or SCI cases where lifetime care costs can reach millions of dollars. UIM coverage is essential for motorcycle riders — the gap between minimum policy limits and actual catastrophic injury damages is typically enormous.

California Insurance Code § 11580.2 UM/UIM coverage applies to motorcycle riders. Motorcycle insurance policies may include their own UM/UIM provisions; auto policies with UM/UIM coverage also extend to the insured person when riding a motorcycle depending on policy language. The specifics of each policy govern — review actual coverage terms, not just the general rule.

Common insurance issues in motorcycle accident cases: liability insurers frequently argue elevated comparative fault percentages for the motorcyclist based on lane-splitting speed or alleged visibility issues; medical payments coverage (MedPay) on a motorcycle policy pays for immediate treatment; and ERISA-governed health plans may assert subrogation liens against any motorcycle accident settlement recovery.

Evidence That Matters in Motorcycle Accident Cases

• Traffic Collision Report. Documents Vehicle Code violations, road conditions, witness information, and the officer’s observations about vehicle positions.
• Helmet — preserved intact. Damage pattern documents impact location and force. Critical in TBI cases for expert analysis correlating impact zone with documented brain injuries.
• Motorcycle — not repaired before inspection. Mechanical defects (tire failure, brake deficiency) may support a product liability claim. EDR/data recorder data may document pre-crash speed and handling inputs.
• Scene photographs — vehicle positions and lane markings. In lane-splitting disputes, the geometry of vehicle positions relative to lane markings establishes compliance with OmniBike Bill requirements.
• Dashcam and surveillance footage. Vehicle dashcam footage, nearby security cameras, and intersection traffic cameras may capture the collision and the lane-change sequence.
• Medical records including neurological imaging. MRI and CT scan results, neuropsychological evaluation reports, and emergency records documenting the mechanism and injuries.
• Expert reconstruction. Accident reconstruction experts analyze vehicle positions, speeds, and the mechanics of the collision — particularly important in lane-splitting fault disputes.